Growth and, proline and carbohydrate content of bean seedlings subjected to drought stress

Abstract

Drought stress in the highlands of Mexico is a limiting factor in bean yields. In this work we studied the physiological responses (growth) and biochemical (soluble carbohydrates and proline) in the radicle of seedlings resistant beans, Pinto Villa and, susceptible to drought Bayo Madero, both of Durango race, in order to identify quick features to measure their reliability for selection of resistance to drought stress. The radicle of the seedlings were subjected to four moisture potentials: -2.07, -0.52, -0.27 megapascals (MPa) and a control -0.16 MPa. For determining the soluble carbohydrates and proline, the potential -0.16 Mpa was removed, since it caused the hypocotyl rot at the junction with the cotyledon, in this case the potential of -0.27 was considered as control. The radicle of both varieties had greater length in the treatments with less stress. In the most critical potential, -2.07 MPa, Pinto Villa, accumulated more proline and sucrose than Bayo Madero, while starch levels were quite similar. Highly significant correlation was observed between the elongation of the radicle with the accumulation of proline, glucose and fructose (r= 0.99 respectively). The accumulation of compatible solutes (glucose, fructose, sucrose and proline) in the radicle developed under conditions of stress, favors its growth in early stages of development. Compatible solutes are suitable as biochemical indicators for selection of varieties resistant to moisture stress during the first three days of germination.